paradisenb

I have 2 bad boot seals on my front right caliper of my 79 SC. I want to rebuild as opposed to replace the entire caliper.

Any problem with rebuilding instead of putting on a new caliper on a race car?

Thx

Larry Herman

No problem at all if done correctly. I did it all the time on my Carrera. I would suggest that you do both, as the left front can't be far behind.

paradisenb

The left front caliper was replaced at the time I bought the car. I guess the seal between the 2 pieces was bad because the entire unit was changed.

Only issue I read was to insert the pistons at a 20 degree angle. What does that mean? I've done this to other cars an never heard of maintaining some angle in the pistons.

Noticed some deterioration on the backs as well. Not crumbling but dry. I'll will be doing them as well.

Also, back pads are at 55% maybe even 60%.
Down to where are they still performing at a high level?

Larry Herman

I don't have a picture of it, but the pistons have a notch in the face of them, to prevent squealing. That notch is the leading edge, and is angled across the face of the piston. That's where the 20 degree setting comes in. I'll see if I can dig up a pic later, or you can always call me.

paradisenb

Larry, here is the article that references the 20 degree angle. Half way down is a pic. It just doesn't make sense. Maybe once I have it disassembled it will come into focus.
http://www.pelicanparts.com/techarti...er_rebuild.htm

I expect the parts on Thursday. I'll call if I get lost. Thanks for the offer to help.

Bill Verburg

post #10

APKhaos

Randy,
Don't split the caliper halves, as you seemed to be suggesting above. Once apart, its near impossible to get them to seal again. All you need to do is remove the pistons. Inspect the pistons, and reuse them if they look clean [no rust pitting] or replace if not. New seals, careful reassembly, and you are good to go. As Larry said, always do both sides. The Pelican article demystifies the 20 degree piston alignment quite well. The secret si to remember that the notch FACES the direction of rotation. You can make a 20 degree guide from almost anything - light aluminum flashing works well, and you can cut it with scissors.

Dave 86 930 Fl

You may want to pick up a brake piston removal wrench as it makes the job much easier and you reduce the risk of damaging a piston. I learned the hard way. I bought my piston wrench here:

http://www.hrpworld.com/index.cfm?fo...action=product

Bill Verburg

Spliting the caliper is no big deal

you will need 8 seals they used to come 8 to a bag, bolts can be hard to source though, the oem Ribes are nla(afaik)
901.351.928.10


the later 4 piston aren't a big deal either, there aren't even any internal seals to deal w/ though replacing the bolts can be a chore

Larry Herman

Finally, you really do not even need that template tool. If you notice, the inner notch is set exactly in line with the axle, and perpendicular to the caliper. You can see it clearly on Bill's Pelican post on the crufty old caliper. It is sitting on it's back and the notch is straight up. Easy to eyeball without the tool.

Chris M.

Or just make a little mark on the caliper body next to the piston notches before you remove them then just put them back in the same spot. I always blow the pistons out with an air compressor. Put a piece of wood in there so they don't blow out and hit each other or you.
Also, Vertex sells rebuilt A calipers for $129 after core. I don't think you can even buy new pistons for less than that.

jaydubya

Get used to rebuilding your calipers on your SC track car. Especially the fronts. It's an easy task once the calipers are off the car - takes me about 10 minutes per caliper.

I keep a couple of extra caliper rebuild kits in my spare parts stash.

paradisenb

I ordered the front repair kits yesterday. I going to get the rears as well. That way all four corner will be done. I'm going to use air because I don't want to spend $175+ for a tool that will see use once a year at most.
I'm not going to split any calipers. I imagine they warp as soon as they are separated due to the constant heating and cooling. I guess they could be resurfaced to make the reseal easier but I'm not interested in that complication.

I examined the pistons a little closer and found the groove. I think once I have one removed I'll be able to understand how they go in.

Do you guys to 2 brake fluids flushes like the guys says in the Pelican article?

If I need pistons I will with the rebuilts from Vertex. Thanks for the tips Chris.

jaydubya

Not sure what you mean by 2 flushes?

Calipers should be emptied of brake fluid before you rebuild them. Less messy that way. Just hook them back up to the car and brake lines, then bleed both the front calipers.

To keep all the brake fluid from draining out while the calipers are removed, I

1) partially depress the brake pedal with a 2x4.
2) cover the end of the hard line with little rubber boots that I picked up at Checker. I think they sell them for plugging unused vacuum lines, come in a pack of 6 or 8 for $2.

I'll bleed the calipers again after my first track session if they feel soft. Sometimes it's tough to get all the air bubbles out the first time.

Regarding getting the pistons out of the bores in the caliper - I just put a 1/2" piece of wood in the caliper between the pistons, hooked up the hose from one of those electric tire pumps to the brake line input, and then turned it on (I don't have compressed air in my home garage). The pistons will push out slowly as the pressure builds up and then finally with a POP. Keep your fingers clear.

I use a little dental pick tool to get the seals out of grooves in the piston bores, but anything long, narrow and pointy should work. Just be careful not to scratch the piston bores. Not really critical though, since the pistons only touch the seals and not the bores in the caliper. Once you have the old seals out, putting in the new seals is a breeze. I lube the new seals with fresh brake fluid, but I don't think it matters much.

Cheers,

Jeff

jaydubya

Oh - interesting story about how I knew my calipers were ready for new seals.

I keep my car in a garage at the track. Showed up one morning to do an open track day, opened the garage door and there were giant puddles of brake fluid around both my front tires! I guess the calipers got a little warm during the previous track day